High-voltage circuit interrupter



Feb. 8, 1949. R. H. AMUNDSON HIGH-VOLTAGE CIRCUIT INTERRUPTER 2 Sheets-Sheet 1 Filed Feb. 25, 1944 I. 5 0v 0 m 7 J1 a INVENTOR farm AM/wM/v Patented Feb. 8, 1949 HIGH-VOLTAGE CIRCUIT m'rsaaurrna Roald H. Amundson, Milwaukee, Wis., assignor to Line Material Company, South Milwaukee, Wis., a corporation of Delaware Application February 25, 1944, Serial No. 523,788

15 Claims.

This invention relates to high voltage circuit interrupters.

In interrupters in which a fuse link is located in an arc channel, it has been found that considerable difficulty is experienced in interrupting high voltage circuits under overload conditions. In order to assist in the interruption various attempts have been made to employ a metallic conducting capsule containing a liquid under pressure which, through the medium of a fusible portion in the capsule, is liberated upon rupture of the fuse link so that the liquid vaporizes and the resulting pressure gas is discharged and tends to interrupt the arc. These attempts have not provcn wholly satisfactory. A fuse link heats up to a considerable extent when it is carrying somewhere near its rated maximum load and this heat was transmitted to the capsule, in the prior devices, thereby raising the pressure in the capsule enormously and also frequently either bursting some portion of the capsule or fusing the fusible portion of the capsule prior to rupture of the fuse link. This defect rendered the prior devices unreliable in their operation.

This invention is designed to overcome the above noted defects and objects of this invention are to provide an interrupter which is capable of interrupting high voltage, heavy duty circuits and which rapidly extinguishes the resulting arc in an effective and reliable manner,

Further objects are to provide a high voltage, heavy duty, drop-out circuit interrupter in which means are employed, such as a tube, for instance, which provide an arc channel with a fusible link located in the arc channel, and to employ a conducting metallic capsule containing a liquid or gas under pressure but thermally insulated from the fuse link so as to prevent the free transmission of heat from the fuse link to the capsule when the fuse link heats up during the time it is carrying current suflicient to heat the link appreciably but not sufficient to melt the fusible section of the link, and to provide means which is so arranged that when the fuse link is ruptured the arc incident thereto then becomes effective to rupture the capsule and liberate pressure gas so that the pressure gas suddenly forms a blast of expanding cooling gas assisting materially in clearing the circuit within the arc channel, the construction thus guarding against inadvertent rupturing of the capsule prior to rupturing of the fuse link, the construction providing for final drop-out action of the fuse tube after the circuit has been interrupted within the arc channel.

Further objects of this invention are to provide a high voltage circuit interrupter in which a fuse link is located in an arc channel and in which it is thermally insulated, as stated hereinabove, from a capsule containing an arc extinguishing agent under pressure, and in which means are provided adjacent the terminal associated with the capsule, which means are designed to radiate heat transmitted to the terminal from the fuse link when the fuse link is carrying current sufficient to heat it appreciably but not sufficient to melt the fusible section of the fuse link, thus additionally guarding against overheating the capsule.

Further objects are to provide means for rigidly holding the capsule in place adjacent the closed end of an arc' channel, and to provide fuse link extracting means externally of the arc channel which has a light weight quick acting portion for extending the arc and quickly extracting any remaining portion of the fuse link from the channel in a direction away from the capsule, the fuse link extracting means coming into play upon rupture of the fuse link at substantially the same instant that the capsule is ruptured and liberates its blast of arc extinguishin gas, the construction being such that after the arc has been extinguished and the blast of gases liberated, the arc will not restrike as the path along which it would have to restrike has been greatly extended by the fuse link extracting means.

Further objects are to provide a high voltage circuit interrupter having a capsule containing liquid under pressure and thermally insulated from a fuse link located in the arc channel associated with means for switching or guiding the are so that the arc is guided directly to the fusible portion of the capsule to insure rupture of the capsule upon rupture of the fuse link without having the heat of the fuse link transmitted to the capsule when the fuse link is carrying current suflicient to heat it appreciably but not sufficient to melt the fusible section of the link, but, nevertheless, insuring the immediate rupture of the capsule when the fuse link is ruptured on overload.

Embodiments of the invention are shown in the accompanying drawings, in which:

Figure 1 is a side elevation, partly in section and partly broken away, showing one form of the invention.

Figure 2 is a sectional view, partly broken away, showing a further form of the invention.

Referring to Figure 1, it will be seen that the circuit interrupter'comprises an upper stationary wardly and outwardly therefrom. The upper terminal of the fuse tube is provided with a fiber inner sleeve 8 conforming approximately to a Sparklet or similar capsule 9 and having a con-' stricted lower portion adapted to engage the corresponding portion of the capsule 9. The capsule is adapted to contain any suitable agent under pressure, such, for example, ,as carbon dioxide,

nitrous oxide, or air. It is provided with a fusible lower end [0. I

It is to be noted that the insulating sleeve 8 extends downwardly beyond the lower end of the capsule 9 and immediately below the downwardly extending portion of the sleeve 8 a metal ring II is positioned. This metal ring is preferably screw threaded into the terminal 5 and has attached to it the strain wire l2 and the fusible section l3 of the fuse link. These portions extend downwardly and are joined to the flexible leader ll of the fuse link. The leader extends downwardly through the arc channel and outwardly from the lower open end thereof, It is to be noted that the tube 3 is screw threaded into the termi- 119.1 5 and is provided with a slidable insulating plug I5 which is held adjacent the upper end of the tube and is adapted to be moved into the recess l5 formed'in the lower portion of the insulating sleeve 8 surrounding the capsule 9 and to thus close off the vents 1 when the fuselink is ruptured. It has an additional function in that it serves to cause switching of the are from the ring ll or-adjacent portion of the terminal 5 to the fusible portion III of the capsule 9 so as to insure melting of the fusible portion and liberation of pressure gas. The slidable plug I5 is suddenly moved upwardly when the fuse link ruptures under overload due to the generation of gases by the action of the are on the fiber lining 4 of the fuse tube below the plug l5. These gases are vented at the upper end of the device through the vents 1 at the beginning of the operation of circuit interruption. The pressure below the plug l5 causes the plug to quickly slide upwardly and close off the vents 1 and, as explained hereinabove, switch the arc to the fusible portion I 0 of the capsule. Arc extinguishing gas is thus liberated and is projected downwardly through the'arc channel as a violent arc extinguishing blast and greatly supplements the normal expulsion action of the device and assists in quicky interrupting the circuit within the arc tube. The gas also acts to cool the arc and thus again assists not only by its sweeping action but by its cooling action in interrupting the arc.

The lower stationary terminal 2 is provided with a hood like portion l6 which has integrally formed therewith a pair of upstanding hook like supporting members I1. It is also provided with a relatively heavy contact spring Ill. The lower portion of the fuse tube 3 has rigidly clamped thereto a sleeve like member I 9 which is provided with a rearwardly and downwardly projecting arm pivoted as indicated at 2| between a pair of arms formed integrally with a main supporting 4 a l lever 22. This main supporting lever 22 is provided with a pair of trunnions 23 removably supported by the hook like portions [1 and is provided with a rearwardly projecting portion 22' which engages the contact spring l8.

The main lever 22 carries a quick acting flipout device or fuse link extractor 24 which is pivoted as indicated at 25 on the main lever. The main lever has an outwardly extending portion 26 and a fuse-link clamping lever indicated by the reference character 21 is also pivoted at 25 on the main lever. A spring 28 urges the flip-out lever or fuse link extracting lever 24 and the fuse link clamping lever 21 in opposite directions. The flexible leader I4 is positioned in a grooved portion of the quick acting fuse link extractor 24 and passes around the outer end of such lever and is clamped between the fuse link clamping lever 21 and the extension 26 of the main lever 22.

It is to be noted that the fuse link extracting lever or flip-out lever 24 is provided with an extended portion 29 which is adapted to strike a part of the fuse link clamping lever 21 after the fuse link extracting lever 24 has moved downwardly a considerable distance. Thereafter the levers 24 and 21 rock as a unit about the pivot point 25 and release the fuse link, allowing any remaining portion of the fuse link to be thrown from the device. The particular construction of flip-out lever and fuse link clamping means forms the subject matter of the patent of William O.

. Schultz, No. 2,378,109, of June 12, 1945, for Fuse constructions.

Assuming that the fuse link is carrying current sufficient to heat the link appreciably but not sufficient to melt the fusible section of the link, it will benoted that although the fuse link heats up, nevertheless it does not materially raise the pressure in the capsule 9 as it is spaced therefrom and is thermally insulated from the capsule. Any heat that passes to the terminal 5 from the fuse link is readily radiated by the terminal and is transmitted to the terminal 5, as will be seen from Figure 1, adjacent the lower portion of the terminal, whereas the metal to metal contact between the capsule and the terminal occurs only at the upper end of the capsule. Consequently the fuse link is thermally insulated from the capsule and does not materially increase the pressure within the capsule. Also it does not heat up the fusible portion In of the capsule and consequently there is no danger of rupturing the capsule prior to rupturing of the fuse link.

Assume that an overload occurs and that the fuse link is ruptured. The gas generated by the are acting on the fiber lining of the fuse tube following rupture of the fuse link suddenly moves the slidable plug l5 which surrounds the fusible section of the fuse link upwardly into the space l6 and closes the vents 1. The vents 1 help this upward action of the plug in that they tend' to relieve pressure immediately above the plug. The plug, however, closes the vents when it moves up but performs an additional and main function of switching the arc to the fusible portion In of the capsule so as to insure that the capsule is ruptured upon rupture of the fuse link. This causes a liberation of pressure gas which expands and cools the arc and sweeps downwardly through the arc channel as a powerful blast, thus interrupting the are within the arc'channel. At the same time the arc is extended within the arc channel by the quick acting flip-out or fuse link extracting lever 24. When this occurs, it will be seen that the main lever 22 is released and it rocks downwardly and rocks the lower end of the fuse tube downwardly and outwardly, thus disengaging the upper rounded portion of the terminal 5 of the fuse tube from the correspondingly rounded portion 3| of the upper stationary terminal or contact I, and allowing the fuse tube to execute drop-out motion rocking about the trunnions 23.

It is to be noted that the upper terminal I may take any desired form, as may also the lower stationary terminal 2, though the quick acting flip-out lever for extracting the fuse link and elongating the arc is a preferred construction and has been described hereinabove. The upper stationary contact or terminal I is resilient and bears downwardly on the fuse tube and normally holds the fuse tube latched thereto. It is provided with a cam like portion 32 so as to ride upwardly when the fuse tube is rocked back into position. It may be provided with a stop 33 to limit the inward rocking motion of the fuse tube.

After the fuse tube has rocked downwardly, it may be removed from the hook like supports l! by means of a switch stick and refused and a new capsule installed. It thereafter may be repositioned on the hook like members IT by means of a switch stick and may be rocked back into position.

The invention may take other forms. For example as shown in Figure 2, additional means as to radiate the heat transmitted to the upper terminal 34 from the fuse link when the fuse link is carrying current sufficient to appreciably heat it but not sufficient to melt the fusible section of the fuse link. The lower portion of the apparatus is identically the same as that previously described in connection with Figure 1. However, it is to be noted that there are no vents formed through the upper terminal 34. It is to be noted particularly, however, that the same construction is followed as that described in Figure 1 whereby the capsule 36 is thermally insulated from the fusible section of the fuse link. The capsule is carried within an insulating sleeve, such as fiber, as indicated at 3! which conforms to the shape of the capsule and holds the capsule rigidly in place in metallic contact at its upper end with the adjacent upper portion of the terminal 34. The fuse link comprises the flexible leader 38, the strain wire 39 and the fusible section 40. The strain wire 39 and fusible section 40 are connected to a metallic ring 4| screwed into the inner portion of the terminal 34. A slidable insulating plug preferably formed of fiber and indicated at 42 is carried in the upper end of the fuse tube 43. This fuse tube may be formed of an outer Bakelite portion and an inner fiber portion as previously described. In this form of the invention the slidable plug 42 moves upwardly when the fuse link is ruptured due to the sudden generation of pressure in the arc channel 44 and causes the switching of the arc from the ring 4| or the adjacent portion of the terminal 34 to the fusible section 45 of the capsule 36, thus allowing the pressure gas to be liberated and to be projected downwardly through the arc channel 44.

It will be seen that this invention provides a high voltage, heavy duty circuit interrupter which is so constructed that the heat from the fuse link is not transmitted to the capsule containing the liquid under pressure but that the capsule instead is insulated from the fuse link. It is to be noted, however, that though there is no direct contact between the fuse link and the capsule, nevertheless means are provided for switching the are so as to insure that the arc is switched to the fusible portion of the capsule.

It is to be noted further that when the fuse link is ruptured, the arc is rapidly extended by the quick acting flip-out fuse link extractor and that after the arc has been extinguished within the fuse tube, it cannot restrike as the distance through which it would have to restrike has been greatly increased by the quick extraction of the fuse link. After the entire operation of extinguishing the are within the fuse tube is over, the fuse tube drops out of position and is thus bodily automatically taken out of the circuit.

It is to be understood that vent openings, such as described in connection with Figure 1, may be provided for the form of the invention shown in Figure 2 and also it is to be understood that the fins, described in connection with Figure 2, may be provided for the form of the invention shown in Figure 1.

Although this invention has been described in considerable detail, it is to be understood that such description is intended as illustrative rather than limiting, as the invention may be variously embodied and is to be interpreted as claimed.

I claim:

1. A circuit interrupter comprising means providing an arc channel, closure means for one end of said channel, the other end of said channel being open, gas liberating means adapted to liberate gas when acted upon by an are, said gas liberating means being located adjacent said closure means, a fuse link within said channel having a fusible section in proximity to said gas liberating means, means adjacent the closure means for anchoring one end of said fuse link, said fuse link extending out of the open end of said channel, and fuse link extracting means located externally of said channel for extracting any remaining portion of said fuse link upon rupture of the fusible portion, said fuse link extracting means being arranged to exert tension on said fuse link which is transmitted to the anchored end of said fuse link.

2. A circuit interrupter comprising means providing an arc channel. closure means for one end of said channel, the other end of said channel being open, gas liberating means adapted to liberate gas when acted upon by an arc, said gas liberating means being located adjacent said closure means, a fuse link within said channel having a fusible section in proximity to said gas liberating means, said fuse link extending out of the open end of said channel, and quick acting fuse link extracting means located externally of said channel for quickly extracting any remaining portion of said fuse link upon rupture of the fusible portion.

3. A circuit interrupter comprising means providing an arc channel, gas liberating means adjacent one end of said arc channel adapted to liberate gas when acted upon by an arc, a terminal adjacent said end of said are channel, the other end of said are channel being open, a terminal adjacent the open end of said are channel, a fuse link within said are channel normally electrically connecting said terminals and extending out of the open end of said are channel, said fuse link being adapted to rupture and form an are on overload, and means for switching said are to a position adjacent said gas liberating means.

4. A circuit interrupter'comprising means providing an arc channel, a first terminal adjacent one end of said channel, a container enclosing material adapted to liberate gas when acted upon by an arc, said container being located adjacent said first terminal, a second terminal, a fuse link within said channel normally electrically connecting said terminals and having a fusible section adjacent said first terminal adapted to rupture and form an are on overload, said fusible section being thermally separated from said container. and means for causing the arc to rupture said container and act upon said material upon rupture of said fuse link. 5. A circuit interrupter comprising means providing an arc channel, a first terminal adjacent one end of said channel, a conducting capsule electrically connected to said first terminal, said capsule having a fusible portion and containing material adapted to liberate gas when acted upon by an arc, a second terminal, a fuse linklocated in said channel normally electrically connecting said first and second terminals and being spaced from said capsule, and means for switching the arc incident to rupture of said fuse link on overload to said capsule.

6. A circuit interrupter comprising means pro-- viding an arc channel, a first terminal adjacent one end of said channel, a conducting capsule electrically connected to said first terminal, said capsule having a fusible portion and containing material adapted to liberate gas when acted upon by an arc, a second terminal, a fuse link located in said channel normally electrically connecting said first and second terminals and being thermally insulated from said capsule, and means for switching the arc incident to rupture of said fuse link on overload to said capsule.

7. A circuit interrupter comprising means providing an arc channel, a first terminal adjacent one end of said channel, a conducting capsule electrically connected to said first terminal, said capsule having a fusible portion and containing material adapted to liberate gas when acted upon by an arc, a second terminal, a fuse link located in said channel normally electrically connecting said first and second terminals and being spaced from said capsule, means for elongating the arc in said are channel incident to rupture of said fuse link on overload, and means for switching the arc to said capsule.

8. A circuit interrupter comprising means providing an arc channel, a first terminal adjacent one end of said channel, a conducting capsule electrically connected to said first terminal and rigidly held in place, said capsule having a fusible portion and containing material adapted to liberate gas when acted upon by an arc, a second terminal, a fuse link located in said channel normally electrically connecting said first and second terminals and being spaced from said capsule, means for elongating the arc incident to rupture of said fuse link on overload in said are channel in a direction away from said capsule, and means for switching the arc to said capsule.

9. A circuit interrupter comprising means providing an arc channel, a first terminal adjacent one end of said channel, a conducting capsule electrically connected to said first terminal, said capsule having a fusible portion and containing material adapted to liberate gas when acted upon acted upon by an arc, a second terminal, a fuse' link located in said channel normally electrically connecting said first and second terminals and being thermally insulated from said capsule, and a movably mounted insulating sleeve in said are channel adapted to be moved by the pressure resulting from the rupture of said fuse link for guiding the arc incident to rupture of said fuse link on overload to the fusible portion of said capsule.

11. A circuit interrupter comprising means providing an arc channel, a first terminal adjacent one end of said channel, gas liberating means adjacent said first terminal adapted to liberate gas when acted upon by an are, a second terminal, a fuse link located within said channel and normally electrically connecting said terminals and having a fusible section adjacent said gas liberating means, said fuse link being thermally insulated from said gas liberating means, and an insulating sleeve surrounding said fusible section and spaced from said gas liberating means and adapted to be moved toward said gas liberating means by the pressure resulting from rupture of said fuse link to thereby guide the arc incident to rupture of said fuse link on overload into proximity to said gas liberating means, said interrupter having venting means between said gas liberating means and said sleeve.

12. A circuit interrupter comprising means providing an arc channel, a first terminal adjacent one end of said channel, gas liberating means adjacent said first terminal adapted to liberate gas when acted upon by an are, a second terminal, a fuse link located within said channel and normally electrically connecting said terminals and having a fusible section adjacent said gas liberating means, said fuse link being thermally insulated from said gas liberating means, and an insulating sleeve surrounding said fusible section and spaced from said gas liberating means and adapted to be moved toward said gas liberating means by the pressure resulting from rupture of said fuse link to thereby guide the arc incident to rupture of said i'use link on overload into proximity to said gas liberating means, said interrupter having venting means between said gas liberating means and said sleeve, said venting means being closed by motion of said sleeve towards said gas liberating means,

13. A drop-out circuit interrupter comprising a body portion of insulating material having an arc channel therein and having an upper contact, an upper stationary contact normally engaging the upper contact of said body portion, a. lower stationary contact, a fuse link electrically connecting the upper contact of said body portion and the lower stationary contact and extending through said are channel, fuse link extracting means controlled by said fuse link and engaging said fuse link adjacent the lower portion of said are channel and releasably supporting said body portion, and means adjacent the upper end of said are channel adapted to liberate gas when acted upon by an are.

14. A circuit interrupter comprising means providing an arc channel, gas liberating means adjacent one end of said are channel adapted to liberate gas when acted upon by an arc, an arcing terminal spaced from said gas liberating means, a second arcing terminal normally electrically connected to said first mentioned arcing terminal, means adapted to separate the terminals and form an are between the terminals, and means for switching said are to a position adjacent said gas liberating means.

15. A circuit interrupter comprising means providing an arc channel, a first terminal adjacent one end of said channel, gas liberating means adjacent said first terminal adapted to liberate gas when acted upon by an are, a second terminal, a fuse link located within said channel and normally electrically connecting said terminals and having a fusible section adjacent said gas liberating means, said fuse link being thermally insulated from said gas liberating means, an insulating sleeve surrounding said 10 fusible section and spaced from said gas liberating means and adapted to be moved to guide the arc incident to the rupture of the fuse link on overload into proximity to said gas liberating means, said interrupter having venting means between said gas liberating means and said sleeve, said venting means being closed by motion of said sleeve towards said gas liberating means, and means located on that side of said sleeve opposite said venting means for generating pressure when acted upon by an arc to move said sleeve.

ROALD H. AMUNDSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 815,804 Eveleth Mar. 20, 1906 1,246,792 Schweitzer et a1, Nov. 13, 1917 1,952,734 Ten Brook Mar. 27, 1934 2,235,666 Birkenmaier Mar. 18, 1941 2,269,130 Schultz Jan. 6, 1942 

